Project Description Sudden cardiac arrest (SCA), a sudden catastrophic loss of the pulse, affects >350,000 in the US annually with a >90% mortality rate. Therefore, improved primary prevention is a major priority. SCA burden is affected by race, socioeconomic status, and potentially ethnicity. Hispanics/Latinos (HL) are the largest and most rapidly growing US minority, but there are no prospective studies of SCA in this subgroup. We performed a 1-yr (2015) prospective pilot study of SCA among all residents of Ventura County, CA (PREdiction of Sudden death in mulTi-ethnic cOmmunities, PRESTO, founded by the PI), with a population distribution of 42.3% HL (>89% Mexican origin) and 48.7% non-Hispanic white (NHW). There were significant differences in the clinical profile of HL (n=71) vs. NHW (n=204). Our pilot data also indicated other unique aspects of SCA in HL, specifically related to women, and the role of obesity. The overall goal of this proposal is to identify ethnicity-specific targets for improved SCA prediction and prevention. The Hispanic Community Health Study/Study of Latinos (HCHS/SOL) is an NIH-funded multi-center cohort study of 16,000 persons of HL origin including 4000 subjects recruited from southern CA (San Diego). The Oregon Sudden Unexpected Death Study (SUDS) is a community-based evaluation ongoing for >16 years (also founded by the PI). We propose to make comparisons between PRESTO HL SCA cases and San Diego HCHS/SOL subjects on the one hand; and between PRESTO NHW SCA cases and Los Angeles Data Repository (LADR) NHW controls, on the other. As a final step, we will attempt to validate our findings from the above analysis in the separate Oregon SUDS, that provides access to an HL subgroup (~76% Mexican origin), NHW and all the same information. Given the lack of epidemiologic data on HL SCA, as well as the important differences in clinical profile between HL and NHW SCA cases identified in our pilot study, ethnicity-specific SCA risk prediction should be evaluated. While our results may not be generalizable to all US HL populations, we believe our study would provide valuable data for HL of primarily Mexican origin. Leveraging the established track record and resources of Ventura PRESTO, HCHS/SOL and Oregon SUDS maximizes the likelihood of achieving this objective.